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SePt- 17, 1929- o. A. coLBY 1,728,786

TERMINAL Filed may 15. 192e [yet y ffy@ Wl SS S: INVENTOR afa-4. a@ j BY Patented Sept. 17,` 1929 UNITED STATES PATENT OFFICE?" ORA A. COLBY, OF IRIVIN, PENNSYLVANI v a, AsseNoP. To wEsTrNGHoUsn Enno'rnro, a MANUFAcTURrNc- COMPANY, A CORPORATION or PiiNNsvLvANIAn TERMINAL Appleman` mea May 15, 192e.v Vserial No. 109,286.y

My invention relates to electric translating devices, and particularly to electric terminals therefor.

An object of my invention is to provide a compact electric terminal that is adapted to be secured to electrically conducting bodies and to be insulated therefrom.

Another object of my invention is to provide a terminal for electric translating de vices that shall be easy to manufacture and compact and rugged in structure.

Another object of my invention is to provide a terminal for electric translating devices that shall have a minimum number of parts and be adapted to have an electric conductor attached to either or both ends thereof, as desired.

In practicing my invention, I provide a pair of cylindrical members which are preferably of tubular form. One of the c ylindrical members is smaller in diameter than the other and is adapted to be inserted within the larger member. A suitable clearance space is provided between the two cylindrical members which is adapted to be occupied by a relativelyT thin helix of magnesium metal. By treating the magnesium metal according to the process described in United States Let- `ters Patent No. 1,451,755. issued to CI B.

Backer, it is transformed into magnesium oxide. During 'the transformation from the metallic to the oxide state, the magnesium undergoessuch change in volume that the cylindrical members are held fixed relatively to each other. The magnesium oxide serves, also, as an electric insulator.

In the single sheet of drawings, Figure 1 is a view, in front elevation, of an electric translating device, such as a heater, in which the terminal member embodying my invention is inserted;

Fig. 2 is an enlarged view7 in longitudinal, vertical section, of a terminal member embodying my invention, showing the magnesium metal in place before oxidation;

Fig. 3 is a view in longitudinal section of the device illustrated in Fig. 2, in which the magnesium metal has been changed or transfo med to magnesium oxide; A

Fig, 4. is a longitudinal, sectional view of a 'from the metallic to angoxide state,

` tending flange portion 23 slight modification of the terminal member illustrated in Figs. 2 and 3, and f y Fig. 5 is a similar viewof a still further modification ofthe terminal member illustrated in Fig. 4.* f

Referring more particularly to FigQQ of the drawing, a terminal member 11 comprises any outer cylindrical member 12 and an inner cylindrical'member 13. The cylindrical member 13 comprises a longitudinally extending portion 141 and a laterally extending flange portion 15.` Thelongitudinally extending portion 14 of the cylindrical mem'- ber 13 is of sufiicient diameter to provide a clearance space lybetween the cylindrical ortion 14; andthe innersurface 17 of the `cylindric'zal member 12. A helix 18 ofeX- pansively oXidiZable material, such as magnesium,'is inserted in the clearance spacel, substantially as illustrated in Fig,y '2 of the drawings. f

By subjecting the terminal member 11 to an atmosphere of steam under high pressure, the magnesium-metalhelix 18 is transformed ,j During the transformation from the metallicy to the` oxide state, the magnesium expands and fills very compactlyto maintain the cylindrical members `12 and 13 in rigid fixed relation to each other. yThe magnesium oxide has a highdielectric strength and serves to insulate, electrically, the `member `13 from the member'lQ. y .f f

In Fig. 3 of the drawings, I have illustrated the member 13 the y space 16 as having a screw-threaded portion 19 whi' h is adapted to registerwitlr a screw-threadedfinember k2O, illustrated in Figjl, whereby the end of an electric resistor or an electric conductor may 'be secured thereto.` y In Fig. l ofthe drawings, I have illus- "trated a modification yof the tubular member i 13 shown in Figs. '2 and 3. The tubular member' 13 comprises a cylindrical portion 21 which has a laterallyeXtending yflange portion 22 yat one end thereof and a laterally eX- located at the other i @ne end of themember 13 is provided 'iv-'threaded portion t et ,drawing ,have

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trated a further modification of the terminal member' 11 in that the cylindrical member 13 is provided with two laterally extending ange portions 24 and a threaded portion 25 which extends through the length of the cylindrical member 13. The cylindrical member 13 is ixed relatively to the cylindrical member 12in the same manner as it is secured in Figs. 3 and 4l of the drawings.

In the particular embodiment shown'in Fig. 5, the tubular member 12 is located in an aperture 26 of a member 27 which may be a portion of an electric heater 0r of any electric translatingfdevice, as the case may be. The cylindrical member 12 may be brazed. soldered or'mechanically attached to the body portion 27, as desired.

ln Fig. 1 of the drawings, I have illustrated a terminal member 11, such as shown in Figs. 2 and 3 ofthe drawings, which is inserted into a body portion 2S of any suitable electric heater. In this particular case, the bottom of the openingy 29', into which the terminal member is inserted, may be filled with a refractory insulating material 30. The cylindrical member may then be brazed, soldered or secured by any other suitable means to the body portion 28 to maintain it in fixed relation therewith.l

lt is to be understood, that the term cylindrical member is not to be limitedto cylinders of circular section for they may be either rectangular orV oval as desired. Although the' drawings show only one member 13 within a member 12, it is also to be understood that I may place two or` more cylindrical members within a single cylindrical member and secure them in place by expan sively oxidized magnesium metal substantially as hereinbefore described.

Thile l have illustrated a few preferred forms of the terminal member embodying my invention, various other modifications may be made ltherein without departing from the spirit and scope of myinvention. I desire, therefore, that onlysuch limitations shall be placed thereon as are imposed by the prior art and the appended claim.

I claim as my invention:

The method of making an electrical terminal which comprises locating a tubular member within another tubular member, partially filling the space therebetween with metallic magnesium, and then expansively oxidizing the metallic magnesium to hold the inner tubular member in the outer tubular member and electrically insulate the two members from each other.

In testimony whereof, I have hereunto subscribed my name this 8th day of May, 1926.

Y ORA A.y COLBY. 

